This is a good work of Science Fiction, although I have mixed feelings about it. It appears that it was always planned because it neatly resolves the situation with Hyperion. However, I thought that Hyperion was partly so good because it was so ambiguous. Also the book ends too happily. Hyperion, had all sorts of grim elements, horror elements and so on. The for the most part happy ending sort of undermines the first novel a bit. It also introduces little that is new to the amazing visuals of the first book. Finally, the religion gets too explained. In other words, I found that it undermined some of the mystery of the first book. I preferred it when I did not know what the Shrike was.
However, having said that, it is still an ingenious and well written book. It is has strong characterization, interesting ideas and a universe that it is full and fascinating. The book is very much literary science fiction. It liberally uses poetry and has a literary sensibility. He moves away from the structure of the first book, which was essentially a series of related short stories with a frame tale. That is so rare these days with pure science fiction authors. Most of all Simmons description of his world with its fantastic surrealistic imagery is the most wonderful thing about it. While he describes little that is new, his description is so good and so fantastic that it is just a delight to read. It has some of the best descriptions of the fantastic ever put to paper. The arresting imagery and literary devices are what makes it interesting. The story itself becomes more conventional as it goes along. The mysteries are resolved well, but they are still resolved.
I will definitely read the whole series and will continue to read Simmons after that. But I have to admit that I wish that he had not succumbed to the modern disease of science fiction of writing series and not individual novels and that these talents had been used in a new story.